Air brake



c. A. CAMPBELL,

- 2,023,757 AIR BRAKE. I

Dec. 10, 1935.

Filed March 23, 1931 5.Shets-Sheet 1 III III I EI QI:

Gtfornegs Dec. 10, 1935.

C. A. CAMPBELL AIR BRAKE 5 Sheets-Sheet 2 Filed March 25, 1931 attorneys E Dec. 10, 1935. c CAMPBELL 2,023,757

AIR BRAKE Filed March 25, 1931 5 Sheets-Sheet 5 Zhwentor mmea w 9 4 34% Gtfornegs Patented Dec. 10, 1935 AIR BRAKE Charles A. Campbell, Watertown, N. Y., assignor to The New York Air Brake Company, a cor-- poration of New Jersey 7 Application March 23, 1931, Serial No. 524,746

50 Claims. (01. 303-36) This invention relates to'air brakes, and particularly to triple valves.

Certain features of the invention are useful both in that type of triple valve which uses a single auxiliary reservoir, and in those types which use more than one reservoir, while other features are useful only in connection with the multiple reservoir types.

For purposes of illustration, the invention will be hereinafter described as applied to a triple valve designed to supply the air from a single reservoir in service and from two reservoirs in emergency applications. The particular type of valve chosen forillustration does notpfunction to vent the brake pipe in emergency, but is used inf conjunction with .a brake pipe vent valve, such a valve being associated as an independent struc-, ture with each triple valve. The invention, ,how- I ever, is not limited in this respect.

From the standpoint of the mechanical structure used, the most important feature of, novelty disclosed in the present. case is the use of a triple slide valve and a graduatingvalve in conjunction with a triple piston and a retard stop,'- in such a manner that after the triple piston and.

valves have moved to restricted recharge and re-' lease position, only the graduating valve and the piston move back to normal recharge position, leaving the triple slide valve in restricted release position.

The area of the graduating valve exposed to auxiliary reservoir pressure is so much less than the area of the triple slide valve that the frictional resistance to motion is far less. Consequently, the retard stop spring can be made lighter, thus permitting the valve to move to restricted release position more readily, and re- I ducing its tendency to overtravel toward application position when returning to normal recharge position. From the standpoint of. mechanical structurethese are substantial advantages.

The peculiar motion of the slide valve an graduating valve, above defined,,permits the introduction of certain valuable flow controls which are important objects of the invention as follows:

In normal release the back flow from the supplemental reservoir to the auxiliary reservoir is 50 at a restricted rate which reduces the tendency toward reapplication and reduces the resistance to motion to restricted recharge and release. The broad idea of controlling such back flow by means of the triple valve and graduating valve 55 is claimed in my Patent No. 1,928,091, granted ,valve.

September 26, 1933, as a continuation of an earlier filed application. 1

In motionfrom normal to restricted recharge and release positions, coordination of the charging passages around' the triple piston and 5 through the graduating and slide valves insures complete motion once motion-is started.

In restricted recharge and. release position the supplemental, reservoirand the brake cylinder are connected to atmosphere through a single 10 exhaust port which is 'controlled'by the retainer It has heretoforeqbeen proposedto connect the supplemental reservoir .to the brake cylinder port in restrictedmelease, but this is apt to have the effect of raisingbrake cylinder pres- 15 sure.. In the present invention the connection is to the exhaust passage. beyondthat restriction.

reservoir in restricted release may be omitted.

which controls the outflow. ,of brake cylinder pressure, and the arrangement permits such proportioning of the parts as will secure the opti- 20 mum restriction of brake cylinder exhaust without the possibility of'increaseof brake cylinder pressure. The broadideaofbleeding the supplemental reservoir in restricted release position is claimed in my Patent No. 1,928,091, grant-, 25

ed September 26,;19 33 above identified. In certain cases it is desirabletoguard against this possibility. Under, certain circumstances, however, the feature of venting the supplemental 30 In normal recharge ai ter,,.restricted release (which is the name adopted for the'position assumed by the parts when the graduating valve 1 and piston movebackto normal from restricted position, leaving the slide valve in abnormal position) a large port is opened between the auxiliary and the supplemental reservoir, the purpose being to dissipate any overcharge in the auxiliary reservoir into the supplemental reservoir. This action is peculiarly effective if the valve functions .to vent the. supplemental reservoir in restricted release position- In this same position, a stabilizing port, which might conveniently be one of the quick service ports, is opened betweenthe slide valve chamber and the brake pipe. -'In"eifect an additional by-pass is opened around the triple piston. Thus I those triple valves which have moved to restricted release positionyi. e'.,'the valves on the forward end of the train, are rendered less sensitiveto reductions of brake ,pipe pressure than they otherwise wouldbe. f' It is exactly these forward triples which are most efiected by erratic functioning of the feed valve on the locomotive, 5

stabilizing port, and by controlling this quick 1 service port by meansof the quick service limiting valve, forming the-subject matter of a prior applicationSerial No. 517,606, filed February 21,. 1931, it is possible togclosethe stabilizing by-pass and thus restorethesensitiveness of-thetriple valve when'brake pipe pressure has been reduced a given amount; Consequently'the quick service limiting valve acquires a new anduseful function in this particular combination. and'is y vation, plan, and lower faceviews of the triple here claimed in thatrelatiom- It may, however,

satisfactorily without it. c Another feature ofthe inventionlis that be cause the triple slide valve staysin'restricted release position, after the triple'piston' moves back to normal recharge position brake' cylinder exhaust ifonce restrioted,- remains restricteduntil a new application is made;

be omitted as the stabilizing port will operate of brake cylinder pressureboth in service andin emergency. This valvei unctions to give a rapid initial rise of pressure, foliowed by a gradualrise. This valve will function .to preventtoo violntin-L itial applications in theevent that a triple valve should stick on-thef first ,brake pipe reduction and respond to asubsequent'additional reduction, aswill be hereihaiterbxplaihed- I The two-stage buildup mechanism herein de-l stagebuild-upmechanisms, any oi-which might be used. One such mechanism which gives a three-stage 'build-up ,and::has developed decided '1 valuable characteristicsfiis illustrated in my Pat- 'ent No. 1,928,091, granted September 26, 1933.

A practical embodiment'ofl the inventiong a's above outlined, is illustrated: in the accompany ing drawings, in which,+- j

Fig; 1 is a'view showing the connection of the; triple valve to the brake jpipejemergency vent valve, supplemental and auxiliary reservoirs, and brake cylinder. i

Fig. 2 is a vertical axial'se'ction through a triple valve embodying the invention {and showing the. connections to the supplemental'and auxiliary reservoirs and brake-cylinder. -In this view the structure isconventionalized to the extent that the various ports are drawn onthe plane of sec-' tion. In-actual practice' a'more compact structure can be secured by asomewhat different location ofports. F g

Fig. 3 shows thequick service-limiting valve which also acts as a limiting valve for the stabil izingport.

Fig. 4 is a fragmentaryview showing a'modification in which quick service air is fed directly to the brake cylinder uncontrolled, by the two Fig. 8 shows the partsin'the position called normal recharge after restricted release. 7

Fig. 9 shows the parts in quick service position.

Fig. 10 shows the partsin full service position. 7 7

Fig. llshows the parts'moving from normal recharge and release to restricted recharge and release. In this view the triple piston and. a portion of the cylinder bushing are shown to bring out the control of the charging flow. 5

Fig. 12 is a view similar to Figs. 6 to 10, inclusive, showing the parts in emergency (or over reduction) position.

Fig. 13 is a plan view of the seat for the triple slide valve showing the actual porting, as contradistinguished from the diagrammatic portingillustrated in Figs. 2 to 12 inclusive.

Figs. 14, 15 and 16 are respectively side eleslide valve as actually constructed. 2 '15 Figs. 17 and 18. are respectively, top plan view,

and lower face view. of the graduating valve as actually constructed.

, g p I I pressure in the brake pipe is controlled by an Another feature'nf-the invention is theuse'; of a two-stage build-upvalve controlling the rise brake pipe vent valve may be of any preferred construction, but is preferably of that type 30 which responds to a brake pipe reduction occurring at a rapid rate. When the valve reg sponds it vents the brake pipe 2| directly to atscribedis illustrated as typicaloi' such multiple f of the triple valve.

Also connectedtothe bracket'fitting 22, and 40 communicating therethrough with the brake pipe II, is the branch pipe 24. This communicates through a cut-out cock 25, centrifugal dust separator 26, and union 21, with the lower case or body 28 of a triple valve whose main body ap- 45 pears at 29. This triple valve1has the usual front cap 3| and retainer'32 and is mounted against a filler piece.33 which in turn is seated on the head end of the auxiliary reservoir 34.

The brake cylinder 35 is mountedon the forward 50 end of the auxiliary reservoir 34. A supple- I mental reservoir is shown at 36 and is connected by the pipej3 |'and fitting 38 with the filler piece 33. The purpose of manner piece 33 is to afford a mount for the triple valve'which will connect it with both reservoirs and the brake cylinder. Refer now to Fig. 2. The body 2915 provided with the usual valve chamber bushing 39 which is formed with the usual fiat valve seat 4 l ,for the triple slide valve 42. The graduating valve 43 isslidable on top of the triple slide valve. The cylinder bushing 44 is of usual construction except that it is formed on its outer side with a groove 45 which serves to connect three feed ports, a relatively large port .46, and two smaller 65 ports 41 and 48, whose total capacity approxie mates the capacity of the port 46, and whose individual capacities are in proportion tothe volumes of the reservoirs 36- and, 34: Y 70 The triple pistonappears at ;49 and has the usual head with a narrow slot 50'which seats on the end of the slide valve bushing and determines the rate of restricted charging. There is th'eusual graduating button 5!. The piston stem 52 has a guiding spider 53 at its end, and

between this spider and a collar 54 the slide valve 42 has limited lost motion. The graduat- -ing valve 43 is closely confined'in a notch in the stem 52 and is held seated by a bow-spring 55. A second bow-spring 55 seats the valve 42.

Threaded into the inner end of the body 29 is a ported member 51 which has a central hub 58 serving as a guide for the forward end of the retard stop 59. At the rear end the stop 59is guided in a bushing 6| threaded into the member 51. It is limited in its forward motion by a flange or collar 62 and is urged forward by a relatively light coil spring 83 which surrounds the siem and is confined between the bushing 6| and the collar 62. Slidably mounted on the :hub 58 is a sleeve54 which carries a lug 65. This lug limits the inward motionof the slide valve 42.

The retard stop 59 coacts solely with the end of the stem 52. Consequently, at the end of restricted release and recharge it moves merely the piston stem 52, piston 49 and graduating valve 48, the slide valve 42 remaining unaffected in its innermost or restricted release position.

The front cap 3| has the usual plug 65 which serves as a guide for the graduating stem. 61. This has near its forwardend the. usual collar 68 which seats on a stop 69 formed in the front cap. A light graduating spring H surrounds the stem 61 andis confined between the nut 66 and the collar 68. Also seated against the stop 89 is a ring 12 having an inward flange 13. This is engaged by the collar- 68 when the stem 81 moves back slightly and then brings into action a second and heavier graduating spring 14 which is confined between a portion of the nut 66 and the inward flange 13 on ring 12.

The parts are so arranged that button,5| engages the end of stem 61 without compressing either spring in quick service. position; compresses spring 'Il until collar 88 engages flange 13 in full service position, and overpowers both springs until the piston 49 seats on the front cap gasket 15 in emergency and over-reduction position. j 1

It will be observed that the guide member 51 projects into a port 16 formed through the member 33 and serving to connect the valve "iamber within the bushing 29 with the interior of the auxiliary reservoir 34. I g

The brake cylinder pipe 11 which extends through the auxiliary reservoir 34to the brake cylinder 35 (this being standard practice in the air brake art) communicates with a passage I8 in the member 33 which registers with the brake cylinder passage 19 in the body 29. The body 29 may be a standard body for an ordinary K- type triple valve now extensively used by North American railways. This body has in-its lower portion a chamber, which; in the K-triple valve is used for the emergency piston. This chamber, in conjunction with a registering chamber formed in the special lower case 28, is used to receive a quick service limiting valve body 8| (see also Fig.8). This body is formed-with a flange 82 to confine the ring gasket 83 which forms a seal between the upper end of the body ket 85 interposed between the lower case 28 and the triple valve body 29. The lower end of the body 84 seats onran annular ported At about midlength there is an annular and thus seals with the lower end of the recess in the lower case 28.

The brake cylindenpassage I9 communicates with an annular passage 81 which surrounds the upper portion of the body 8|. and communicates through. an interchangeable choke 88 with a space 89. Thechoke 88 controls the'r ate of flow of air to'the brake cylinder in the second stage of emergency and is made interchangeable so that different chokes may be substituted and the rate of flow inthe second stage set to any desired value. r 1 p p The body 8| is in the form of an inverted cup and inserted through its lower end is a member 9|. (Refer. particularly to Fig. 3.) This makes a tight joint by means of the gasket 92, with the body 8| and has a central passage 93 leading from the ported valve seat 94 for. thepin valve 95. The lower end ofthe member 9| is formed with a convex seat 96 fora flexible diaphragm 91. A convex diaphragm clampingring 98 forms a seat for. the lower side of the diaphragm 91 and isheld'in place by a ported annular nut 99. Thepin valve 'is seated in a central hub made up of a thrust member ||l| and'a nut I82 threaded into the member I8| through the center of the diaphragm. The member also coacts withthe nut 99 to limit downward motion of the diaphragm. I I

. The pin valve 95 is, shown as of a construction familiar in governor. tops and feed valves, but may be of any suitable type in which the pin valve is free to aline itself with the seat 94. A coiled compression spring I03 is confined be tween the members 9| and; |82 and acts to urge the diaphragm 91 downward, that is,in a valve opening direction. 2 l V The brake cylinderbuild-upv delay mechanism is located in the lower part of the lower case 28. In Fig. 2 it is shown with its axis parallel with the axis of the valve chamber bushing 39, but in the valve as customarilyconstructed, a more can be secured, by locating the axis at right angles to the axis of the bushing39. This arrangement is suggested in Fig. l. v

The delay valve mechanism is mounted in two alincd boresv separated by a partition W5. Inserted from one side is a bushing structure having a hub portion I85 which projects through and fills an opening in the partition |05,,the flange 101 which seats on -a gasket |88,;and a ported cup-like portion I09 which is engaged and held inward by the plug IN. The plug is threaded into and cioses the opening in the body 28. v

On the hub portion; I06 is formed a seat 2 for thecut-ofi valve ||3. This isurged in a closing direction .by the coiled .compression spring I I4 and is guided by a stern; I I5, which is longitudinally sidable in the bushing I86.

Under release conditions, and in the first stages of an application, the valve H3 is held open by a piston H6, which, in its inward position, engages the stem N5 of valve H3. The piston 8 slides in a bushing H! which has at its inner end a rim' H8. The piston 8 carries at its inner end a gasket ||9which seats against the rim 8 so that when the piston H6 is in itsinner position arelatively smalliarea of the piston is subject to pressure in the chamber |2|.

There is a bridging port |22 formed through and around the bushing from the annular space outside the rim 8 to'the space to the right of the piston H6. This port is closed by tween the inner end of the piston H6" and an annular spring seat I29 sustained by the gasketI24 and ring I25. I V

Thepurpose ofjthe construction illustratedj'is to permit the use of, a relatively long spring I28 so that the resistance of the spring I28 will not build up with undue rapidity, as the piston I'I6 moves outward. The" construction is such that as pressure in" the chamber 'I2I builds up, a value will be reached at which the piston'II6 starts to overpower-spring I28; Initial movement of the piston cutwa'rd increas'es the effective area of the piston subject to pressure in'the chamber I 2|, and almost simultaneously closes the port I22. Consequently, thepiston II6 moves to its extreme right'hand position in which it seats against the gasket I24. Since the piston seats on the gasket in each limiting position and moves rapidly between these twopositions, it is not essential that the piston II6 fit closely in the bushing I I1. A good sliding fit is all that is necessary'.-

Branch pipe '24 communicates through'the union 21 and strainer I3I with three passages.

Of these, passage I32 leads to a drain cup I33; passage I34' leads to the space to the left of the triple piston 49; and passage I35 leads to the space'outside the member 9I, and thence through the opening I36 to thespace above the diaphragm 91. When the valve 95 is unseated this space is in communication through-the seat,

and bore93 with the passage I31 which leads through-the members 8|, 28 and 29 to the quick service-port I38 'on the slide valve'seat. I 'Fromthe space' I39 with which the supple- 1 mental reservoir pipe 31 communicates, there is a passage I4I which leadsto the space" I42'beneath thediaphragm 81. There isalsoa passage I43 which'connects with the supplemental reservoir ports I'44 and I45in-theslide valve seat."

There are two passages I46 and I41 which con-' nect the spac'e 'IZI to the right of thepartition I and the space I 48 to the left of the partition, respectively, with the chamber. 81 which is in communication with the brake cylinder pipe 19. Thus the spaces I48 and I2I-on opposite sides of the partition I05 are both at brake cylinder pressure, the function of the partition being to prevent air rushing through the valve seat II2 from impinging-'directlyon the end' of the piston I IG. Y Y

It is not essential that the'valve stem I I 5 have a particularly close fit-in the hub I06. 1

The space 89 is in communication with the space I49 to theleft of the valve seat II2 by way of a passage I5I formedpartly' in the'insert'8l and partly inthelower case 28 and body 29. The

space 89 is in direct communication with three ports' in the slide valve seat 4I a quick service port I52; a portI53 for exhaust flowyand a port I54 for service and emergency flow. There is an exhaust port I55 which communicates by way of -.the annular passage' I56 with the retainer pipe I51.

Two possible alternative arrangements'of the I is a stabilizing port I6I1, and release this registers with the quick service 'port I38, but at that 'quick service port I52 are indicated in Figs. 4

and 5, respectively. In Fig. 4, the port I52a leadsto the space 81 instead of to the space 88.

In this, as in the preferred form,the ultimate flow is tothe brake cylinder, but iniFig. 4 this flow is not controlled by the valve H3, as it is in the arrangment of Fig. 2.

In Fig.5, the port I52b leads to atmosphere so that the quick service venting willoccur directly to the atmosphere, instead of to the brake cylinder. I

The slide valve 42 is ported as follows: There In restricted recharge pipe under control '0: the pin valve 85. There are two quick service ports I 63 and I64 which register with the quick service ports I38 and I52 in quick service "position and are then bridged by the recess I65 in the graduating valve. I These ports are devoid of function in other positions. I

There is an exhaust recess I66 in the slide valve which in normal release position connects theports I53 and I55. In restricted recharge and release position and in normal recharge after restricted release, port I55, and port I66 with port I53. Ports I66 and I61 are connected by'a'restrictedpassage I68 which, in the positions of Figs. land 8, restricts the release flow from the brake cylinder.

' The port I61 has an extension I68 which leads to the upper face of the slide valve. There is a supplemental reservoirport. "I which extends through the slide yal've from top to bottom. In restricted release and recharge position the port 'I1I registers with port I44 and is connected with 0 port I69 .by means of recess I 12 in the graduating valve. 1 w

When the graduating valve 43 moves back from 'the restricted release and recharge position of Fig. '7 to normal recharge after restricted release (Fig. 8), the recess I12 moves out of register with the port HI, 7 and port I13 of large capacity formed in the graduating valve connects port I1I with'the slide valve chamber. Port I14 extends throughthe slide valve 42 from topto bottom and, in normal release position, registers with port' 'l44 and with a throttling'port I 15 in the graduating valve 43'. These ports do not function in'other' positions of the valve.

There is a through*port-'ITIB Which extends from top to bottom of the slide valve 42, and is controlled by the graduatingvalve 43. This is the service port. In quickservice position (Fig.

9) it is cleared by the graduating valve and is In fill-1 a" I There is an emergency portI11 which extends 0 through the slide valve 42 from top' to bottom and is not controlled by the graduating valve. In emergency'position (Fig.lZ) this'registers with theport I54.'

The actual porting of the seat 4I and the 70 valves" and 43 differs from that shown in the diagrams in that in the actual structure certain of: the ports perform functions shown in the diagram as performed'by twov distinct ports.

I61registers with port 30 Before attempting to describe the actual porting, the functions of the valves and the various characteristic flows will be described. With these functions clearly in mind, it will berelatively simple to understand the actual construction of the slide and graduating valves.

OPERATION ward end of thctrain. Consequently the triple valves on the forwardcars will move'to restricted release position (Fig. 7)' and those on the rear cars will move to normal release position (Fig. 6)

Normal recharge and release On the rear cars the rise of brake pipe pressure will be gradual'and the triple valves willibe shifted to normal release position (Fig. 6). It has been assumed that the release follows afservice application. Consequently, thepressure in the auxiliary reservoir "34, which alone fed ,air to the brake cylinder, will be reduced, while pressure in the supplemental reservoir 36 willrbe at the normal value.

When the 'slide-valve and graduating valve reach the position of Fig. 6, air from the sup lemental reservoir 36 will start flowing to the valve chamber by way of pipe 31, passage I43, ports I44, I14 and I15. Inasmuch. as port I15 is restricted, the back flow from the supplemental reservoir will be slow, and, consequently, will not build up pressure in the auxiliary reservior faster than brake pipe pressure is rising. Hence, there. will be no tendency for the triple valves to move toward service or quick service position. This tendency would exist in a marked degree except fo'rthe throttling action of the port I15. The triple piston 49 stands between the port 46 and the port 41 so that the normal charging rate from the brake-pipe to' the auxiliary. reservoir exists. It will be understood that after pressures in the auxiliary reservoir 34 and supplemental reservoir 36 have equalized, the two reservoirs willbe charged to normal pressure at the same time. This implies an ultimate reversalfof flow through the passage I43. The brake .cylinder is exhausted through port I53, recess I66 and port I55. Valve H3, if closed, will open against the resistance of light spring I I4.

Restricted recharge and release Onv the forward cars the rise of brake pipe pressure is much more rapid. On the. cars very near the locomotive the brake pipe pressure acting on piston 49 will readily overpower spring 63, moving the piston inward until it seats against 'the end of bushing ,36 at which time the slot 56' determines the charging "rate. V

Ihefartherthe car is from the locomotive the less pronounced is the brake pipe pressure rise, and a point will be reached where the triple pistons start to move toward restricted release position and have a tendency to falter and stop before they get there. The arrangement of the virtually eliminates this faltering tendency, and this may best be explained with reference to Fig. 11.

shift all the triple valves, and then The'jinltialmotionof the piston 49, blanks port 41 andfrom then on the rate of charging flow is limited to thecapacity of the port 48. Th'ecapacities of' th'el ports 41 and 48 fa're' approximately proportional'flto the volumes of the res- 5 ervoirs 36 and 34, respectivel so that the initialmovement of'the piston ,from normalre charge position cutsdown the rate of charging flow and thuschecks the flow fromthe brake pipe andconservesbrake pipe pressure. I j 10 This same initial'motion carries the port I13 I out'of register with port I44 and stops the charging flow to the supplemental reservoir (after emergency) or (after service) prevents any back fl ow from the. supplemental reservoir. l5

The effect c initial motionof the valve toward restricted release 'positionis, consequentlyjsuch as to insure a completion of motion to restricted release, at which time charging flow is limited to the capacity of th'ejgroove 56. a v

"- Restricted recharge and release position is shown in Fig. .7. In this position-the valvechainbar is cut off from the supplemental reservoir ports I44 and trend the-supplemental reservoir I44 is connectedby port I1I, recess I12,'exten- 'sion' I 69, port I61, with the exhaust port I551 so that if the'r'etainer valve 32 is open, the supplemental reservoir is vented directly to atmosphere.

In some cases such venting of the supplemental "reservoir is'not desired, and in such case,' th'e re- 0 -'cess I12 and extension port I69 are omitted. The brake cylinder is exhausted through port's I53,

cavity 66, restriction I68, port I61 and port/I55.

7' Normal recharge after restricted release Whenbrake pipe and auxiliary reservoir pressu es approach equalization, the retard stop spring 63 will restore the piston 49 to its normal position. This will shift valve 43, but notvalve 42, so thatfthe parts will assume the position of Fig. 40 '8,'nbrrnal recharge after restricted release. The recharge rate around the piston 49 will be restored to the maximum capacity of the port 46.

The'valve-42 will remain in its abnormal posi-' tion in which brake cylinder: exhaust is still I throttled,'so that any remaining air will be discharged from the 'brake cylinder' through port I53, recessl66, restriction I68 and ports I61 and I The relativelylarge port I13 in the graduating valve willnow register with'the port I1I in the slide valve which in turn is in register with thesupplemental reservoirport I44.

Conseduentlmthe slide valve chamber and the supplemental reservoir are in ,free communication with each other, and any overcharge in the 55 auxiliary reservoir willbe quickly dissipated into the supplemental reservoir. This actionwillbe.

imore pronounced if pressure fluid is bled from the supplemental reservoir in restricted recharge and release, buteven if the. supplemental res- O ervoir is not vented, there will be a partial dissipation of the excesspressure in the auxiliary reservoir, Inthis position the stabilizingport I6I is in register'with the quick service port 138 and the stabilizing port I62 in the graduating valve registers with thestabilizingport I6I so that a passage is open from the slide valve cham- ,ber directly to the brake pipe by way of ports I62,

IBI, I38, passage I31,bore 93, opening 36, passage I35. Thus minor reductions of brake pipe pressure, such as might be caused by an erratic feed valve, will not cause undesired application. of the brakes- As pointedout, the triple valves on the forward cars are the only ones thus stabilized.

The strength of the spring I63 is such that if scribed in my prior applicationlabove-ide brake pipe pressure is-a definite amountbelow -supplemental,reservoir pressure, say for example,

sixjpounds perssquare" inch, the valve;S"wi1l v the chamber'89 ofthebrak'e cylinder is limited V .to'the capacity offthechoke' 88. e s 5 close. 7 While the valve, '95 was primarily devised to limi'toquickfserviceventingfitjalso performs the function or closing'the stabilizing .port asf'soon a's ajclefi'nite reductionof brake'pipejpressure has bee'nmade. 1 Consequentlyjin the present relation the quick service limitingyalve which wasfdeled,

performs a new and additional fujnjction Experience with this'valve has shown that the stabilizgin'g ports" can" be. made (large? enough to dissipate any ordinary overcharge in thesu pplemental reservoir, thus serving the double purpose of preventing undesired reapplications and assisting in the: recharge" of thebrakerpipe I I Quick service a,

i service-position the 5| has just engaged the graduating stemgfil and the ,parts are in the position shown in E ig,: 9.

, The service port I16 lS just starting toregister with port;I54,'.while.,ports I63 and I B4 are-in register with ports I38 and I 52 -and are bridged by recess;I65in the graduating valve. This permits brake pipe air to flowby way of passage I35, opening I36 and bore 93-, passage I3I,-,ports I38, J53, 165, I64, I52 .to chamber 89; This venting will continue until brake-pipe pressure hasv dropped adefinite amount, here assumedtobe six pounds below supplemental reservoir pressure at which time valve 95 will close and-terminate the venting flow; With the valve as ordinarily constructed, valve 95 willclose before piston I H6 moves and permits valve II3Vto. close.

' Consequently, quick service venting into the space. 89f is virtuallylthe same as quick service .venting into the space ,81. If it is desired to place this venting definitely beyond 'intejerence' by valve I I3, thearrangementv shown in'fFig.;4

- may be adopted, in whichflthel quick service port I 52a discharges: directly into the space" 81",, or

if his desiredto dischargef theairevented 'in quick service directly to atmosphere, the arrangement shown in, Fig. 5! may betadopted in which ,thequick service port I52b'leadsto, atmosphere.

Quick service, venting accelerateslthe :propaga tionof the service pressure reduction throughout thehtrain, and hastens the response. of the triple valve. Y

1 Full service, i

7 Full service position is illustrated in Fig; '10 In this position the quickservice ports'a'r e out of registen'and the service port I16 is in full register with theport I54; This allows flow from the auxiliary reservoir aloneto'the brake cylinder by way of space 89, passage "I5I, through valve seat H2, chamber I48, and thence by port I41 and f space B'It'o the brake cylinder passage, ex-' tehsionl'IB and brake cylinder pipe '11.

The-rising brake cylinder pressure in chamber 81 is clmlmunicated by way of'port I46 to chainber I 2I. When it reaches a value determined by the exposed areaof the piston I16 and the strength of the spring I28,j-th'e pisto'nIIIi will start to move to-the' rig-ht. It will be-assumed'that the piston-starts to movev when brakefcylinder pres- 'sure reaches a value of'fifteen 'poun'ds'per square finch, though otherrvalfuesmay be adopted.

The initial'movement closes the port: I22 and exposes-the'entire areaof the piston IIGt'obrake cylinder pressureso that the piston moves'outward to its limit of motion andseats against the e the emergency "vent valve 23 will function and V vent the'brake pipe. The piston 49 will move, outfnumbered ports in are giventhe same reference numerals; 45

gasket I24. .The effect is to permit valvegII3 to close under the urge offspring H4 and pressure in the chamber '89. From then on thefiow from i In the event :that-brake'pipe pressureis reduced at a rate, morerapid than service reductlon rate,

ward andseatyongasket I5, and the valve will K855111118, the position shown in Fig. 12.,- In this position supplemental reservoir airwill bedeliv- {ered to the'slideyalve chamber through port I45 which is .then fully exposed, so that'supplemental reservoir air and auxiliary reservoir air will both flow to chamber 89 by -way of ports fll and I54. I From chamber 89 the fiowto the brake cylinder will be thatalready, described with reference to full service; The fifteen pounds brake cylinder pressure necess'aryto cause closure of the valve 'II3 will be attained somewhat more rapidly and the flowthrough the choke 88 will be more rapid becauseport I 1 I- is substantially larger than port 25 .116 and because the volume, of the supplemental reservoir 36 isadded to the auxiliary reservoir volume. s

' Actual porting of values I Theop erat'ionof the valves has now been traced from thedia'grai'nmatic"standpoint; and while it is entirely practicable to construct the'valves with all the ports shown in thediagrarmit is possible v to simplify the ccnstruction by causing'certain I of the portsfto perform double'functionsa Figs. 13 to 18' inclusive show 'preferred" porting and the structure shown inthese figures isfunctiona'lly identicalwith that shown in the remain- "ing figures, except Figstand 5, in which, as 40 c-explainedi the discharge port for quick service venting ismodified. Wherever the ports in Figs; 13 to 18'are identicalln 'function'with similarly the remaining figures they Referring first toFig. 13, there isa single supplementalreservolr port indicated by the legend I44 in all release positions, I45 in emergency. Instead'of three ports I52, I53 and I54 leading-to 'the chamber 8 9,fthere are twoports, one correv sponding to port I52'and' theother to port I53,

and "eachof them-performing aportion of the 'servi'ce'performed bythe port I54. Consequently, one portbearsthe legend I53 in release, I54 in service, and theother bears the legend I52 in 5 quick service, I54'in emergency.

'The ports I 35and I55 correspond to similarly numbered ports in the diagram."

On the slidevalve. 42 the ports are numbered similarly to the diagram. It should be noted that theemergency port III takes the form of a I notch cut in-the side, of the slide valve; Many of the remaining ports are produced by drilling and plugging, but as' illustr'ationof thiswould 5 fUSingfthe general path of the ports has 'a-lone-beentra'ced.

v -In Figs 14 andl fi ,theaport I68 is'shown as drilled through fromwthe lower face of'the' valve, and open to said lower face." It is blanked-on the seat in allTpositiohs except service and quick 70 service, where it registers merely withexhaust port I55. It then establishes'atmospheric pres sureyin the ports I66 and I61, andby thus increasing 'theseating pressure on, the valve increasesit's frictional resistance to motion.

It will be observed that the graduating valve 43 contains no port corresponding to the port I15. The edge of the graduating valve 43 coacts with the port H4 in the slide valve 42 to perform'the desired function. V

Theporting described in Figs. 13. tov 18, inclusive, affords a simple and compact arrangement and the best so far developed, but is by-no means the only arrangement which might be adoptedto embody theprinciples shown in diagram in Figs. 6 to 12, inclusive.

As already explained, certain features of the invention may be embodied in triple valves differing from-that illustrated. For example, it is not essential that a separate brakepipe vent 'valve always be used; it is not essential to every 'tions, or both. -Various multiple stage mechanisms are used and might beadapted to use with triple slide valves ported to embody the invention here disclosed, or certain features thereof.

The idea of connecting the brake pipe to the slide valve chamber in normal recharge following restricted release may be adopted whether or not a supplemental reservoir is used, and. if a supplemental reservoir is used, whether or not this reservoir is vented in restricted release position.

The feature of providing for diiferential flow rate between the supplemental and auxiliary reservoirs in'normal release and recharge position and in normal recharge following restricted release is useful, irrespective of the presence or absence of the stabilizing connection between the supplemental reservoir and the brake pipe in normal recharge following restricted release.

The use of a quick service port controlled by'a quick service limiting valve as; a part of the stabilizing connection in normal recharge following restricted release is a convenient and highly desirable arrangement. The same arrangement could be used whether this stabilizing port has or. has not a quick service function. In such case, control by a diaphragm valve, such as the valve 95, might be dispensed with, or might be exerted by other approximately equivalent mechanism.

In other words, the mechanism here disclosed involves a number of useful features, various of which are individually useful, and all or many of which inv combination produce advantageous results. Consequently, no necessary limitation to the exact structure herein disclosed is implied.

I claim:

1. The combination of a brake pipe; a reservoir; a brake controlling valve device including a valve actuating abutment interposed between the brake pipe and reservoir and arranged to respond to differentials between the pressures therein, said device having a normal and an abnormal release position in each of whichit affords a path for flow between the brake pipe and the reservoir; and means rendered effective by motion of said valve device to said abnormal. and then to said normal position to afiord an additional flow path between said brake pipe and reservoir.

2. The combination with an automatic brake valve of the type including an actuatingpiston and having a normal charging position and an abnormal charging position to which last the valve is moved by excessive brake pipe pressure, of means comprising ports in the automatic valve rendered effective by motion of the automatic valve to said abnormal andback to said normal position to open a by-pass around said actuating piston.

3. The combination. with an automatic brake valve of the typeincluding an actuating piston and having a normal charging position and an abnormal charging position to which last the valve is moved by excessive brake pipe pressure, of means rendered efi'ective by motion of the triple valve to said abnormal and back to said normal position to open a by-pass' aroundsaid actuat- 10 ing piston; and means independent of the automatic valve and responsive to a low brake pipe pressure for closing said by-pass. v

4. The combination with an automatic-brake valve of the type having a normal charging posi-' tion and an abnormal charging position, to which last the valve is moved by excessive brake pipe pressure, said valve being adapted to control charging of, and supply of air from, an auxiliary reservoir and a supplemental reservoir; means controlledv by saidautomatic valve for connecting said reservoirs in normal charging position;

and means rendered effective by the motion-of the automatic valve to abnormalpand back to normal charging position. to change the flow capacity of the connection between the reservoirs.

5. The combination with an automatic brake valve of the type having a normal charging position and an abnormal charging position, to which last the valve 'ismoved by excessive brake pipe pressure, said valve being adapted to control charging of, and supply of air from, an auxiliary reservoir and a supplemental reservoir; means controlled by said automatic valve for connecting said reservoirs in normal charging position; means rendered effective by the motion of the automatic valve to abnormal and back to normal charging position to change the flow capacity of the connection between the reservoirs; and 40 means rendered eifective by :such motion to reduce the sensitiveness of said automatic valve to fluctuations of brake pipe pressure.

6. The combination with a triple valve of the type having anormal charging position and an abnormal charging position, to which last the valve is moved by excessive brake pipe pressure, said valve being adapted to control charging of, and supply of air from, an auxiliary reservoir and a supplemental reservoir, said valve including a triple piston; means controlled bysaid triple valve for connecting said reservoirs in nor 7 mal charging position; and means rendered effective by the motion of the triple valve to abnormal and back to normal charging position to change the flow capacity of the connection between the reservoirs, and to open a'by-pass around said triple piston,

'7. The combination with a triple valve of the type having a normal charging position and an abnormal charging position, to which last the valve is moved by excessive brake pipe pressure. said valve being adapted to control charging of, andsupply of air'from, an auxiliary reservoir and a supplemental reservoir, said valve including atriple piston; means controlled by said triple valve-for connecting said reservoirs in normal charging position; means rendered effective by the motionof the-triple valve to abnormal and back to normalcharging position to change the 7 flowv capacity of theconnection between the reservoirs,- and to open a by-pass around said triple piston; and means independent of the triple valve and responsive to a low brake pipe pressure for closing said by-pass.

valve chamber having aslide valve seat; a slide valve on said seat; a graduating valve; a triple piston subject on one side to brake pipe pressure and on the other to pressure in said slide, valve chamber, said piston being arranged to actuate said valves andhaving lost motion relatively to said slide valve; a yielding retard stop reacting against motion of the piston and serving when brake pipe pressure is normal to arrest the piston and valves innormal position, but capable of yieldingunder abnormalrise of brake pipe pressure to permit the piston and valves to move to an abnormal position,"'and thereafter serving to restore the piston and graduating valve to normal position while-the slide valve remains in abnormal position; there being coacting ports in said seat and slide valve, and controlled by said graduating valve, said'ports' being so arranged as to open, inthe last-named position, apassage from the slide valve chamber to the brake pipe. I

9. Ina triple valve, the combination of a slide valve-chamber having a slide ,valve seat;: a slide valve on said seat;a graduating valve; "a triple piston subject on one sideto brake pipe pressure and on the other topressure in said slide valve chamber, said piston being arranged to actuate said valves and having lost motion relatively to said slide valve; a yielding retard stop reacting against motion, of the piston and serving when brake pipe pressure is normal to arrest the piston and valves in normal position, but capable of yielding under abnormal rise of brake pipe pressure to permit the piston and valves to move to an abnormal position, and thereafter serving to restore the piston and graduating valveto normal position while the slide valve remains in abnormal position; therebeing coacting ports in said seat and slide valve, and controlled by said.

graduating valve, said ports being so arranged as to open, in the last-named position, a passage from the slide valve chamber to the brake pipe; and secondary valve means responsive to brake pipe pressure and controlling the" last-named passage.

10. In an automatic brake valve, the combina-' tion of a slide valve chamber having a slide valve seat; a slide valve onsaid seat; a graduating valve; an actuating piston subject on one side to brake pipe pressure and on the other to pressure in said slide valve chamber, said piston being arranged to actuate said valves andhaving lost motion relatively to said slide valve; a yielding retard stop reacting against motion of the piston and serving when brake pipe pressure is normal to arrest thepiston and valves in normal position, but-capable of yielding under abnormal rise of brake pipe pressure to permit the piston and'valves to move to an abnormal position, and

thereafter serving to restore the piston and grad uating valve to normal-position while the slide valve remains in abnormal position; an auxiliary reservoir connected with said slide valve chamber; a'supplemental reservoir; there being'coact-- ing ports in said seat and slide valve, controlled by said graduating valve, and serving when both valves are in normal position to open arestricted communication betweenthe slide valve chamber and the supplemental reservoir, when both valves are in abnormal position to isolate, the supplernental reservoir from the slide valve chamber, and when the graduating valve is in normal and the slide valvin abnormal position to open free communication between said slide valve chamber and said supplemental reservoir.

11. Inan automatic brake valve, the combination of a slide valve chamber having a slide valve seat; a slide valve on said seat; a graduating valve; an actuating piston subjecton one side piston and valves to move to'an abnormal posi-- tion, and thereafter serving to restore the piston and graduating valve to normal position while the-slide valve'remains in abnormal .position, an auxiliary reservoir connected with said slide valve chamber; asupplemental reservoir;

there being coacting ports in said seat and slide valve, controlled by said graduating valve, and serving when both valves are in normal position to open a restricted-communication between the slide valve chamber and the supplemental reser voir, when both valves are in abnormal position to isolate the supplemental reservoir from the slide valve "chamber, and when the graduating valve is in normal and'the slide valve in abnormal position to open free communication between said slide valve chamber and said supplemental reservoir and open a passage from the slide valve chamber to the brake pipe.

12. Ina triple valve, the combination of a slide valve chamber having a slide valve seat; a slide valve'on said seat; a graduating valve; a triple chamber, said piston being arrangedto actuate said valves and having lost motion relatively to 7 said slide valve; a yielding retard stop reacting against motion" of the piston and serving when brake pipe pressure is normal to arrest the piston andvalves in normal position, but capable of yielding under abnormal rise of brake pipe pressure to permit the piston and valves to move to anabnormal position, and thereafter serving to'restore the piston and graduating valve to normal positiondwhile the'slide valve remains in abnormal position; an auxiliary reservoir connected with said slide valve chamber; a supplemental reservoir; there being coacting ports in said seat and slide 'valve, controlled by said graduating valve, and serving when both valves are in normal position to open arestricted communication between the slide valve chamber and .i

the supplemental reservoir, when both valves are in abnormal position to isolate the supplemental reservoir from the slide valve chamber, and

whenthe graduating valve is in normal and the slidevalve in abnormal position to open free communication between said slide valve chamber and said supplemental reservoir and open a passage from the slide valve chamber to the brake pipe; and secondary valve means responsive to brake pipe pressure and controlling the last- .named passage.

13; In a triple valve, the combination of a side valve chamber having a slide valve seat;

a slide valveon said seat; a graduating valve; a

triple piston-subject. on one side to brake pipe pressure and on the'other to pressure in said slide valve chamber, said piston being arranged 'to actuate said valves and having lost motion relatively tosaid slide valve; a yielding retard stop reacting against'motlon of the piston and controlled by said graduating valve, and serving when both valves are in normal position to open a restricted communication between the slide valve chamber and the supplemental reservoir, when both valves are in abnormal positionito isolate the supplemental reservoirfrom the slide valve chamber, and when the graduating valve is in normal and the slidevalve in abnormal position to open free communication betweensaid slide valve chamber-and said supplemental reser-' voir and open a passage from the slide valve chamber to the brake pipe; secondary valve means controlling the, last-named passage; a pressure motor connectedto actuate said secondary valve means and subject to brake pipe pressure in a valve-openingdirection and to supplemental reservoir pressure in a valve-closing d'rection; and means for biasing said secondary v valve means in an opening direction.-

14. In a triple valve, the combination of a slide valve chamber having a slide valve seat; a slide valve on said seat; a graduating valve; a triple piston subject on one side to brake pipe pressure and on the other to pressure in saidslide valve chamber, said piston being arranged to actuate said valves and having lostmotion relatively to said slide'valve; a yielding retard stop reacting against motion of the piston and servingwhen brake pipe pressure is normal to arrest the piston and valves. in normal position, but capable of yielding under abnormal rise of brake-pipe pressure to permit the piston and valves to move to an abnormal position, and thereafter serving to restore the piston and graduating valve to normal position while the slide valve remains in abnormal position; an auxiliary reservoir connected with said slide valve chamber; a supplemental reservoir; there being coacting ports in said seat and slide valve, controlled by said graduating valve, and serving when both valves are innormal position to open a restricted communication-between the slide valvechamber andthe supplementalreservoir, when both valvesare in abnormal position to isolate the supplemental reservoirfrom the slide valve chamber, andwhen the graduating valve is in normal and the slide valve in abnormal position to open free communication betweensaid slide valve chamber and said supplemental reservoir and open a passage from the slide valve chamber to the brake pipe; secondary valve means controlling the last-named passage; a pressure motorv connected to actuate said secondary valve means'and subject to brake pipe pressure in a valveeopening direction and to supplemental reservoir pressure in avalve..- closing direction; and a spring urging said secondary valve means inan opening direction.

35. In a triple valve, the combination of a slide valve chamber having a slide valve seat; a slide valve on said seat; a graduating valve; a triple piston subject on one side to: brake pipe pressure and on the other to pressure insaid slideyalve chamber, said pistonbeing arranged to actuate said valves and having lost. motion relatively to said slide valve; 9. yielding retard stop reacting 7 against motion of the piston and serving when brakepipe pressure is normal to arrest the piston and valves in normal position, but capable of yielding under abnormal rise of brake pipe pressure to permit the piston and valves to move to an abnormal position, and thereafter serving torestore the piston and graduating valve to normal position while the slide valve remains in abnormal position; an auxiliary reservoir connected 10 withsaid slide .valve ..chamber; 'a supplemental reservoir; there being coacting ports'in said seat and slide valve, controlled by said graduating valve, and serving when both valves are in normal position to open a restricted communication between the slide valve chamberand the supplemental reservoir, when both valves arein abnormal position to isolate the supplemental reservoir from the slide valve chamber and vent said reservoir, and when the graduating valve is in normal and the slide valve in abnormal position to open freecommunication between said slide valve chamber and said supplemental reservoir.

16, In a triple valve, the combination of a slide valve chamber ha ving a slide valve seat; a slide valve on said seat; a graduating valve; 'a triple a piston subject on one side to brake pipe pressure and on the other to pressure in said slide valve chamber, said piston being arranged 'to actuate said valves and having lost motion relatively to said slide valve; a yielding retard stop reacting against motion of the piston and serving when brake pipe pressure is normal to arrest the piston and valves in normal position, but capable of yielding under abnormal rise of brake pipe pressure to permit the piston and valves to move to an abnormal position, and thereafter serving to restore the piston and graduating valve to normal position whilethe slide valve remains in abnormal position; an auxiliary reservoir connected with 0 said slide valve chamber; a supplemental reservoir; there being coacting ports in said seat and 1 I slide valve, controlled by saidlgraduating valve, andservingwhen both valves are in normal position to'opena restricted communication'between the slide valve chamber and the supplemental reservoir, whenboth valves arein abnormal'position to isolate the supplemental reservoir from the slide valve chamber and vent said reservoir,

and when the graduating valve is in normal and her, said piston being arranged to actuate said valves and having lost motion relatively to said slide valve; a yielding retard stop, reacting against motion of the piston and servinglwhen brake pipe pressure'is normal to arrest the piston and valves in normal position, but capable of yielding under abnormal rise of brake pipe pressure to permit the piston and valves to'move to an abnormal position, andthereafter serving to restore the piston and graduating valve to normal 7 position while the slide valve remains in abnormal position; an auxiliary reservoir connected with said slide valve chamber; a. supplemental reservoir; there being coacting ports in said seat and slide valve, controlled by said graduating 7 valve, and serving when both valves are in normal position to open a restricted communication between the" slide valve chamber and the.

supplemental reservoir, when both valves are in abnormal position to isolate the supplemental reservoircfrom' the slide valve chamber andv'ent said reservoirjand when the graduating valve is in normal and theslide valve in abnormal-position to open free'communication between said sl de valve chamber and said supplemental reservoir,

and open a passage from the slide valve chamber to the brake pipe; andsecondary' valveineans responsive to brake pipe pressure and'controlling the last-named passage.

18. In a triple'valve, the combination of a slide valve chamber having a slide valve seat; a S11d valve on saidseat; a graduatingvalve; a triple piston'subject on one side to brake pipe pressure and on the other to pressure in said slide .valve chamber, said piston'being arranged to actuate said valves and having lost motion'relatively to said slide valve; a yielding retard stopreacting against motion of'the piston and servingwhen brakepipe pressure is normal to arrest the pistonv and valves in normal position, but capable of yielding under abnormal rise of brake pipe pressure to permit the piston and valves to move to an abnormal position, and thereafter serving to restore the piston and graduating valve'to normal position ,while the slide valve remains in'abnormal position; an auxiliary. reservoir connected with said slide valve chamber; a supplemental reservoir; there being ccacting ports in said seatand' slide valve, controlled by said graduatingi'valve, and serving when both valves are in normal position to open a restricted communication between valve-closing direction; and'means for biasing said secondary valvemeans in 'an openingdircc- 19. In a triple valve, the combination of 'a slide valve chamber having a slide valve seat, a slide valve on said-seat; a'graduating valve;;'a'triple piston subject on one side .to brake pipe pressure and on the otherto pressure in said slide valve chamber; said piston being arrangedto actuate said valves and having lost motion-relatively to said slide valve; a yielding retard stop reacting against motion of the pistonand serving when brake'pipe pressure is normal to arrest the piston and-valves in normal position, but capable of yielding under abnormal riseofbrake pipe pres- I sure to "permit the piston and valves to move to :an abnormal position, and thereafter serving to' restore the piston and graduating valveto normal positioniwhile the slide valve remains in abnormal positionfian auxiliary'reservoir connected withs'aid slide valve chamber; a supplemental reservoir; there being coacting ports in said seat and slide valve, controlled by said graduating valve, and serving when both valves are in normal position to open a restricted communication between'the slide valve chamber and the supplemental reservoir, when bothvalves-are in abnormal position to isolate the supplemental reservoir from the slide valve chamber and vent saidreservoir, and when the graduating valve is in normal and the slide valve in abnormal positionto open free communication between said slide valve chamber and "said supplemental reservoir, and

open a'passage-from the slide valve chamber to the-brake pipe; secondary valve means control- Eling' the'last-named passage; a pressure motor connected to actuate said secondary valve means and subject to brake pipe pressure in a valveopening direction and to supplemental'reservoir pressure in a valve-closing direction; and a spring urging said'seco'ndary valvemeans in an' opening direction-J I 20. In an automatic brake valve, the combination of a slide valve chamber, having'a' valve seat and adapted-for connection withan auxiliary reservoir; a slidevalve on said seat; agraduating "valve; an actuating piston subject on one side' to brake pipe pressure and on the; other to pressure in the slide valve chamber, said piston being arranged to actuate said valves and having lost motion relativelyt'o said slide valve; and a yielding retard stop reactingagainst motion of the pist'on'and serving when brake pipe pressure rises normally to arrest'the piston andboth valves in 'normalposition, but capable of yielding under abnormal rise of brake pipe pressure to permit the piston and-both valves to move to abnormal position, and thereafter serving to. shift the piston and graduating'valve to normal position, the slide valve remaining'irr abnormal position; there being in saidjseat a quick service port'leading from thebrake pipe and a -'quick service port leadin'g'to'a-point oirdischargeandports in the slide valve controlledby the graduating valve, and serving in quick servicepositionto connect said. quickservice ports-together, and when the 'graduating'valve isinnormal and the slide valve in abnormal position 'to connectfthe first-named quick service port with the slide'valve chamber.

21. In a triple valve,the 'combination of'a slide valvechamber, having a valve seatand adapted for connection with an auxiliary reservoir; a slide valve on said seat; a graduating valve;-a triple piston subject on one sideto brake pipe pressure and on the other to pressure inv the slide valve chamber, saidpiston being arranged to actuate said valvesand having lost motion relativelyto said slide valve; and ayielding retard stop reacting againstmotion of the piston and a v serving-when brake pipe pressure risesnormally to arrest the piston and both valves innormal position, but'capable of yielding under'abnormal rise of brake pipe pressure to'permit'the piston remaining in abnormal position, there being in said seat a quick service port leading from the and both valveslto move to abnormal position, and thereafter serving to shift thepiston and graduatingvalve to .normaliposition, the'slide valve' brake pipe and a quick service port leading to 1a point'of discharge, and ports-in the-slide'valve controlled by the graduating valve, and serving in quick service position toconnect said quick service ports together, and when thegraduatlng valve is in normal and the slide valve in'abnormal position to'conncct the first-named quick service port with the slide valvechamber; and secondary valve means responsive'to brake pipe pressure and controlling thefirst-named quick service port; I

22. In'a triple valve, the combination of a slide valve chamber, having a valve seat and adapted for connection with an auxiliary reservoir; a slide valve on said seat; a graduating valve; a triple piston subject on one side to brake pipe pressure and on the other to pressure in the slide valve chamber, said piston being arranged to actuate said valves and having lost motion relatively to said slide valve; a yielding retard stop reacting against motion of the piston and serving when brake pipe pressure rises normally to arrestthe piston and both valves in normal position, but capable of yielding under abnormal rise of brake pipe pressure to permit the piston and both valves to move to abnormal position, and thereafter serving to shift the piston and graduating valve to normal position, the slide valve remaining in abnormal position; and a supplemental reservoir; there being in said seat a quick service port leading from the brake pipe, a quickservice port leading to a point of discharge, and a supplemental reservoir port to which the supplemental reservoir is connected, and there being ports in the slide valve controlled by the graduating valve, and serving in quick service position to connect said quick service ports together, serving when both valves are in normalposition to establish restricted communication between the slide valve chamber and the supplemental reservoir port, and serving when the graduating valve is in normal and the Slide valve in abnormal position to establishfree communication between theslide valve chamber and the supplemental reservoir port. t

23, In a triple valve, the combination of a slide valve chamber, having a valve seat and adapted for connection with an auxiliary reservoir; a slide valveon said seat; a graduatingva lvetia triple piston subject on one side to brake pipe pressure and on the other to pressure in the slide valve chamber, said piston being arranged to actuate said valves andhaving lost motion relatively to'said slide valve; a yielding retard stop reacting against motion of, the piston and serving when brake pipe pressure rises normally to arrest the piston and both valves in normal position, but capable of yielding under abnormal rise of brake pipe pressureto permit the piston and both valves to move to abnormalposition, and thereafter serving to shift the piston and graduating valve to normalfposition, the slide valve remaining in abnormal position; and a supplemental reservoir; there being'in said seat a quick service port leading fromthe brake pipe, aquick service port leading to a point of discharge, and a supplemental reservoir port to which the supplemental reservoir is connectedand there being ports in the slide valve controlled by the graduating valve, and serving-in quick service position to connect said quick service ports together, serving when both valves are in normal position to establish restricted communication between the slide valve chamber and the supplemental reservoir port and serving when the graduating valve is in normal and the slide valve in abnormal position to establish free communication between the slide valve chamber andQthe supplemental reservoir port, and communicationbetween the slide valve chamber and the first-named quick service port, 7 I.

, 2 4. Ina triple valve, the combination of a slide valve chamber, havinga valve seatand adapted for connection Withan auxiliary reservoir; a slide valve on said seat; ,a graduating valve; a triple piston subject on one side to brake pipe pressure and on the other to pressure in the slide valve chamber, said piston being arranged to actuate said valves and having lost motion relatively to said slide valve; 21 yielding retard stopreacting against motion of the piston and serving when brake pipe pressure rises normally to arrest the piston and both valves in normalposition, but capable of yielding under abnormal rise of brake pipe pressure to permit the piston and both, valves to move to abnormal position, and thereafter, serving to shift the piston andgraduating valve to normal position, the slide valve remaining in abnormal position; a supplemental reservoir; therelbeingfin said seat a quick service port leading from the brake pipe, a quick service port leading to a point of discharge, and a supplemental reservoir port 'to which the supplemental reservoir is connected, and there being ports in the slide valve controlled by the graduating valve, and serving in quick service position to connect said quick service port-s together, serving when both valvesar'e in normal position to establish'restricted communication between the slide valve chamber and the supplemental reservoir port and serving when the graduating valve is in normal and the slide valve in abnormal position to establish free communication between the slide valve chamber and the supplemental reservoir port,'and communication between the slide valve chamber and the firstnamed quickservice port; and secondary valve meanssubject to brake 'pipe pressure and .con-

trolling, the first-named quick service port.

25., In a triple valve, the, combination ,of a slide valve. chamber, having a. valve seat and adapted for connection withan auxiliary reservoir;,as1ide valve on said seat a graduating valve; n

a triple piston subject on one side to brake fpipe reacting against motion of the pistonand servpressure and on the other to pressure in the slide ,valve chamber, saidpiston being arranged to actuate said valves and having" lost motion ,rela- 'tively to said slide valve; a yielding"retard stop ing whenbrake pipe pressure rises normally to arrest the piston and both valves innormal position, but capableof yielding under abnormal rise of brake pipe pressure to permit the piston andbothvalves to move to abn'ormalposition,

and thereafter serving to shift the piston and graduating, valve to normal position, the slide valve remaining in abnormal position; a supplemental reservoir j there being in said seat a quick service port leading from the'brake pipe, a quick service port leading to a" point of discharge, and a supplemental reservoir port to which the supplemental reservoir is connected, and there being portsin the slide valve controlled by the graduating valve, and serving in quick service position to connect said quick service ports together, serving when both valves are in normal position to esnected to actuate said secondary valve and subject] in a valve-opening, directionstoibrake pipe pressure and'in a valve-closing direction to supplemental reservoir pressure; and meansfor biasnamed quick service port; a pressure motor coning said secondary valve in an opening'dir'ection.

26. In .a triple valve, the combination of a slide valve chamber, having a valve seat and adapted for connection with an auxiliary reser- V voir; a slide valve on said sea t; a graduating valve; a triple piston subject on'one side to brake pipe pressure and on the other to pressure in the V slide valve chamber, said piston being arranged to actuate said valves and having lost motion relatively to said slide valve; a yielding retardstop reacting against motion of the'piston and serving when'brake pipe pressure risesnormally to arin an opening direction. V W 7 2 7 'In atriple valve,- the combinationfota slide valve chamber, having. a valve seat and adapted for connection with an auxiliary reserbrake pipe'pressure and on the other to pres-5 sureinithe slide valve chamber, said piston being rest the piston and both valves in normal-position, but capableof yielding under, abnormal rise of brake pipe pressure to permit'tl'ie piston andv both valves to'move to abnormal position, and thereafter serving to shift thepistonandgraduating valve to normal position, the slide valve remaining in abnormal position; asupplemental reservoir; there being in'said seat aquick 'se'rvice port leading from the brake pipe, a quick,

service port leading'to a point of discharge, and

a supplemental reservoir port to which the supplemental reservoiris connected, and there being ports in the, slide valve controlled by'the graduating valve, and serving in quickfservice position to connect said quick service portstogether, serving when both valves are in normal position to establish restricted communication between the slidevalve chamber and the supplemental reservoir port and serving when the graduating valve is in normal and the slide valve inabnormal position 1 to, establish free communication between theslide valve'chamber and the supplementalfreservoir port, and communicationbetween the "slide valve chamber and the firstnamed quick service port; a secondaryvalve con trolling the firste-named quick 'se'rvicefport; a

pressure motor connected to actuate saidsec=' ondary valve and subject in a valve-ope'ning directionto brake pipe pressure and in'a valve- 7 closing direction to supplemental reservoir pressure; and a spring urging said secondary valve voir; a slide valve on said seat; a graduating valve;"a triple piston subject on one s ide to arrangedto actuate said valvesand having lost motion relatively tosaid slide valve; a yielding retard stop reacting against motion of the piston and serving when brake pipe pressure rises 7 normally to arrest the piston andboth valves 'in normal position, but capable of yielding un der abnormal rise of brake; pipe pressure to permit the piston and both valves to move to abnormal position, and thereafter servingto 'shift the piston and-graduating valve to normalposition, theslide valve remaining in abnormal position;

and a supplemental reservoirithere being j in said 'seata quickservice port leading from the brake pipepaquickservice portfleading to'a pointhf discharge, an exhaust port, and a supe plernental reservoir port, and there 'be in'g' ports in the slide valve controlled by the graduating,

valve, serving in quick service position'to conrie'ct said quick service portstogether, serving when both valves are'in normal position, to establish restricted; communication between the slide valve chamber and supplemental reservoir port, serving when both valves s em abnormal position ,to isolate the supplemental reservoir port from the slidef'valve chamberTand connect said-port with'said exhaust port, and serving when the graduating valveis in normal and the slide valveis in abnormal position to establish free communication between the slide valve chamber and the supplemental reservoir port.

28. In a triple valve, the combination of a slide valve chamber, having a valve seat and adapted for" connection withan auxiliary reservoir; a slide valve on said seat; a graduating valve; 9, triple and on the other to pressure'in' the slide valve chamber, said piston being arranged to actuate said valves and having lost motion relatively to said'slide valve; a yielding retard stop reacting against motion of the pistonand serving when brake pipe pressure rises normally to arrest the piston and both valves in normal position, but capableoi yielding under abnormal rise of brake pipe pressure to permit the piston and both valves to move to abnormal position, and thereafter serving to shift the piston and'graduating valve to normal position, the slide valve remaining in abnormal position; and a supplemental reservoir;

' piston subject on one'side to brake pipe pressure there being in said seat a quick service port lead port with said exhaust port, and servimz when the graduating valve is in: normal and the slide valve is-'in{ abnormal position toestablish tree communication between the slide valve chamber and the supplementalreservoir port,"and.ccm-' munication between the'slide valve chamber and 'th'efirst-n'am'ed quick service port.

29. I n a triple valve,'the combinationof a slide valve chamber,- having a valve seat and adapted ifor connection with an auxiliary reservoir; a slide valve on said seat; agraduating valvef'a triple piston subject on one side to brake pipe pressure andon the other to pressure inthe slidevalve chamber, said, piston being arranged to actuate said valves and having; lost motion relatively to said slide valve; a yielding retard stop reacting againstmotion of the piston and serving when brake pipe pressurerises to normal value torar- 5 rest the piston and bothrvalves, in normal position, but capable oi yielding under abnormalrise of brake pipe pressure to permit the piston and "both valvesto move to abnormal position, and

thereafter serving to shift the piston and graduating valve to normal: position, the slide, valve remaining in abnormal position; a supplemental reservoir; there being in 'saiciseat a quick service port leading from the brake pipe, a quick service port leading to apoint of discharge, an exhaust port, and'a supplemental reservoir port, and there being ports in the slide valve controlled by the ,graduatihgvalve, serving" in quick service posi- :t'ion' to connect said quick service ports together,

serving 'when'both valves'are'in normal position,

"to establish restricted communication between the slidev'alve chamber and supplemental reservoir port, serving when both valves are in abnormal position to isolatethe supplemental reservoir 7 port fromtheslide valve chamber and connect 1 said portvvvith said exhaustport, and serving when the'graduating valve is in normal and the slide .valve is in abnormalposition to establish free valve chamber having a valve seat and adapted for connection with an'auxiliary reservoir; a slide valve on said seat; a graduating valve} a triple piston subject on one side to'brake pipe pressure and on the other to pressure in said slide valve chamber, said piston being arranged to actuate said valves and having lost motio'n relatively to said slide valve; and a yielding retard stop reacting against motion of the piston and serving when brake pipe pressure rises normally in release, to arrest the piston and both valves in normal position, but capable of yielding to permit the piston, in response to abnormal riseof brake pipe pressure, to shift both valves to abnormal position, and thereafter serving to shiftthe piston and graduating valve to normal position, the slide valve remaining in abnormal position} there being a supplemental reservoir port in said slide valve seat; a pair of ports in the slide valve, the first of which registers with said seat port in the normal, and the second of which registers with said seat port in the abnormal position of the slide valve, and a pair of ports of diiferent capacity in the graduating valve, the small capacity port registering with the first slide valve port when both valves are in normal position and the large capacity port registering with the second slide valve port when the graduating valve is in normal andthe slide valve in abnormal position.

31. In a triple valve, the combination of a slide valve chamber having a valve seat and adapted for connection with an auxiliary reservoir; a slide valve on said seat; a graduating valve; a triple piston subject on one side to brake pipe pressure and on the other to pressure in said slide valve chamber, said piston being arranged to actuate said valves and having lost motion relatively to said slide valve; and a yielding retardstop reacting againstmotion of the piston and serving when brake pipe'pressure rises normally in release, to arrest the piston and both valves in normal position, but capable of yielding to permit the piston, in response to abnormal rise of brake pipe pressure, toshift both valves to abnormal position, and thereafter serving to shift the piston and graduating valve to normal position, the slide valve remaining in abnormal position; there being a supplemental reservoir port in said slide valve seat and two ports in the slide valve which register with said seat port selectively in normal-and abnormal positions of said slide valve, and two ports in the graduating valve which register in alternation with each other with corresponding ones of said slide valve-ports at the limits of said fllost motion of the slide valve, the two ports in one of said valves being of different flow capacities.

32. In a triple valve, the combination of aslide valve chamber having a valve seat andadapted for connection with an auxiliary reservoir; a slide valve on said seat; a graduating valve; a triple piston subject on one side to brake pipe pressure and on the other to pressure in said slide valve chamber, said piston being arranged to actuate saidvalvesand having 'lostmotion relatively to said slide valve; and a yielding retard stop reacting against motion of the piston and serving when brake pipe pressure rises normally in release, to arrest the piston and both'valves in normal position, but capable of yielding'to permit the piston, in response to abnormal rise of brake pipe pressure, to' shift both valves to abnormal position, and thereafter serving to shift the piston and graduating valve to normal position, the slide valve remaining in abnormal position; there being a supplemental reservoir port in said'slide valve seat and two ports in the slide valve which register with said seat port selectively in normal and abnormal positions of said slidevalve, and two ports in the graduating valve which register in alternation with each other with corresponding ones of said slide valve ports at the limits of said lost motion of the slide valve, the two ports in the graduating valve being of difierent flow capacities.

33. In an automatic brake valve, the combination of an actuating piston-having a normal recharge position and a restricted recharge position; a slide valvehaving a lost motion connection with said'piston and having a normal release position and a restricted release position, and having ports forproviding'insaid release positions connection between the auxiliary and a supplemental reservoir; a graduating valve controlling the lastnamed ports by motion relatively to the slide valve; and a yielding retard stop tending to arrest said piston and valves in position for normal release and recharge, but capable of yielding under excessive rise of brake pipe pressure to permit movement to position to restrict release and recharge, said retard stop' serving to'restore the piston and graduating valve to normal recharge position while the slide valve remains in restricted release position. 7

34. In an automatic brake valve, the combination of an actuating piston having a normal recharge position and a restricted recharge position; a slide valve having a lost motion connection with said piston and having a normal release position and a restricted release position, and

having ports for providing in said release positions connection between the auxiliary and a supplemental reservoir; a graduating valve controlling the last-named ports by motion relativelyto the slide valve; and a yielding retard stop'ten'ding to arrest said piston and valves in position for normal release and recharge, but capable of yielding under, excessive rise of brake pipe pressure to permit movement to position to restrict release and recharge, said retard stop serving to restore the piston and graduating valve to normal recharge position while the slide valve remains in restricted release position, said graduating valve 7 functioning in conjunction with the slide valve triple piston having a normal recharge position and a restricted recharge position; a valve cha'mber provided with a valve seat. having a stabiliz'ing port and a supplemental reservoir port; a slide valvemounted on said seat, and having a lost motion connection with said piston, and having a normal release position and a restricted release position, and having ports which in said release positionsregisterselectively with said supplemental reservoir port, and a stabilizing port which in restricted release positionvregisters with the stabilizing port in said seat; a graduating valve controlling the slide valve ports above named; and a yielding retard stop tending to arrest said piston and valves in normal release and recharge position, but capable of yielding under excessive rise of brake pipe pressure to permit movement of the piston and valves to restricted release and recharge position, said retard stop serving, to restore'the piston and graduating valve to normal recharge position while the slide valve remains in restricted release position, said graduating valve functioning inconjunction with the slide valve to establishrestricted communication between the slide valvechamber and the supplemental reservoir port in normal release and recharge position and s free communication between saidchamber and port, and communication between said chamber and stabilizing port when. the piston and arrest said piston and valves in position for normal release and vrechargefbut capable of yielding under excessive rise of brake pipe pressure to permit movement to position to restrict release and rechargefsaid retard stop serving to restore the piston andfgraduating valve to normal recharge position while the slide valve remains in restricted release position, said graduating valve functioning, in conjunction with the slide valve to establish restricted communication between said reservoirs in normal release and recharge position, and free communication between said reservoirs when the piston andgraduating valve are in normal recharge positionandthe slide valve is in restricted release position, and to vent" the supplemental reservoir inre'stri cted release and recharge position. r f

37. In a triple valve, the'combination of a triple piston having a normalrecharge' position andja restricted recharge position; a slide valve chamber having a seat provided with afstabilizing port leadinggto the brake pipe, a'supp'lemental reser- 'voir port and an exhaust port a slide valvemovable on said'seat and having a normal release position and restricted release position, said slide valve being provided with ports which in said release positions register selectively with said s'upplemental reservoir port, and with a stabilizing port which in restricted release position registers withthe stabilizing port-in said seat; a graduating valve eontrolling theabove named ports in the slide valve; 2; yielding retard stop tending to. arrest said piston and valves in normal release "and recharge 'position,jbut capable of yielding ,under excessive rise or brake pipe pressure to permit motion to restricted recharge and release position, said' retard stop serving to restore the piston and graduating valve to'normal'recharge position while the slide valve remains in restricted 4 1. An au'to matic brakevalveof the equalizing recharge position and slide valve is in restricted release position to establish free communication from said reservoir port to the slide valve chamher and communication between the slide valve 10 chamber and, said stabilizing port, and in re,-

stricted recharge andrreleaseposition, to connect saidsupplemental reservoir port with said exhaust port.

38.. In a triple valve, the combinationof a triple piston having a normal recharge position and a restricted recharge position; a valve chamber provided with a valve seat having a stabilizing port and a supplemental reservoir port; a slide i valve mounted on said seat and having a lost motion connectioniwith said piston, and having a normalrelease positionand a restricted re lease' position, and having ports which in said release positions register selectively with said supplemental reservoir port, and a stabilizing port which in restrictedrelease position registers withthe stabilizing port in said seat; a graduating valve controlling the slide valve ports above named; and a yielding retard stop tending to arrest saidpiston and valves in normal release 0 and recharge position, but capable of yielding under excessive rise of brake pipe pressure to permit movement of the piston and valves to restricted release and recharge position, said retard stop serving to restore. theepiston and graduatingvalve to normal recharge position while the slide valve remains in restricted release position, said graduating valve functioning in conjunctionv with the slide valve to establish restricted communication between the slide valve 0 chamber and the supplemental reservoir port in normal releaseand recharge position and free communication between said chamber and port, and communication between said chamber and stabilizing p-ort when the piston and graduating valve are in normal recharge position, and the slidevalve isin restricted release position; and means responsive to the initial portion of a-brake pipe pressure reduction for, closing said stabilizing portwhen said pressure has been reduced a given 5() amount r 39. An automatic brake valve of the equalizing type adapted for connection with a brake. pipe, brake cylinder andauxiliary reservoir, and having a'plurality of release positions, said valve 5 including a passage additional to the reservoir charging passage, connectingthe brake pipe and auxiliary reservoir, and-opened in one of said release positions only.

40. An automatic brake valve-of the equalizing i type adapted for connection with a brake pipe, brake cylinder and auxiliary reservoir, and havingia normal recharge position, a restricted recharge position and a .normalrecharge position to which the .valve moves. from restricted recharge position, said valve including a passage additional to the charging passage,. and open fin the las'tnamed normalv recharge position only,

to connect. thebrake pipe andauxiliary reser-,

voir.

type adapted forucennection with a brake pipe, brake cylinder and auxiliary reservoir, and having three release and" recharge positions, the first of which is initially assumed by triple valves adjacent the engineers brake valve, the second of which is assumed by the remaining valves in the train, and the third of which is subsequently assumed by those valves which move to the first release position, said valves including stabilizing ports distinct from the reservoir charging passage and opened by motion of the valves to said third position to connect the brake pipe and auxiliary reservoir.

42. The combination with an automatic brake valve, as defined in claim 41, of valve means independent of such automatic valve, controlling flow through said stabilizing ports, subject to brake pipe pressure and arranged to close upon a definite reduction of brake pipe pressure.

43. In a triple valve adapted for connection with a brake pipe, brake'cylinder, and auxiliary reservoir, the combination of a valve unit comprising a triple piston, triple slide valve and graduating valve,the triple piston controlling a reservoir charging port, the slide valve controlling release of the brakes, and the triple slide and graduating valve conjointly controlling flow from the auxiliary reservoir to the brake cylinder,

the triple piston actuating said valves and hav-' ing lost motion relatively to one of said valves; and a yielding retard stop reacting against the triple piston in release position, said valve unit including a port controlled by said valves and opened upon 'motion of said piston against the resistance of said retard stop and back under the urge of said retard stop, to connect said reservoir and brake pipe independently of said reservoircharging port.

44. The combination of a brake pipe; a brake cylinder; an auxiliary reservoir; a supplemental reservoir; and a triple valve, said triple valve including a triple piston, triple slide valve actuated thereby, yielding retard stop, and a slide valve chamber connected with the auxiliary reservoir and having a slide valve seat, there king in the seat an exhaust port, a brake cylinder port and a supplemental reservoir port, and there being in the slide valve ports which connect the brake cylinder and exhaust ports without or with the interposition of a flow-retarding constriction according as the triple piston is arrested by or overpowers said retard stop, and a port which connects the supplemental reservoir port with said exhaust port beyond said constriction when the piston overpowers the retard stop.

45. The combination of a brake pipe; a brake cylinder; an auxiliary reservoir; a supplemental reservoir; and a triple valve, said triple valve including a triple piston, a triple slide valve having lost motion relatively thereto, a graduating valve actuated by the triple piston, a retard stop reacting against the triple piston to resist motion from normal to restricted release and recharge positions, and a slide valve chamber connected with the auxiliary reservoir and having a slide valve seat, there being in the seat an exhaust port, a brake cylinder port, and a supplemental reservoir port, there being in the slide valve ports which connect the brake cylinder and exhaust ports without or with the interposition of a flowretarding constriction according as the triple pisthe rimof the actuating piston and a restricted 1 recharge position in which such charging flow is restricted at a point spaced from the rim of the piston, of means for partially restricting charging flow by the initial motion toward restricted recharge position, said means comprising a pair 15 of ports through which, in parallel, the charging flow normally occurs, one of said ports being so located as to be blanked by said piston in such initial motion.

47. The structure of claim 46, further characg, terized in that the charging flow is normally to an auxiliary and a supplemental reservoir, and the automatic valve acts to cut off the flow to the supplemental reservoir as the valve starts to restricted recharge position, the ratio of the flow capacity of the port which isblanked by thepiston to the flow capacity of the other port approximating the ratio of volumes of the supplemental and auxiliary reservoirs.

48. A brake valve mechanism comprising in combination a body adapted for connection with a brake pipe and a reservoir; an abutment in said body arranged to be actuated by the pressure differential between brake pipe and reservoir; and

valve means arranged to be actuated by said 3 abutment and controlling the sensitiveness of said abutment to reductions of brake pipe pressure from the normal running pressure, said valve means being set by a temporary excessive rise of brake pipe pressure to reduce such sensitiveness. 4Q 49. A brake valve mechanism comprising in combination a body adapt-ed for connection with a brake pipe and a reservoir; an abutment in said body arranged to be actuated by the pressure differential between brake pipe and reservoir; and 5 means operatively associated with said abutment, and arranged to afford normal communication between the brake pipe and reservoir when brake pipe pressure rises normally, and an increased communication when brake pipe pressure returns 5 to normal after rising abnormally high.

50. A brake valve mechanism comprising in combination a body adapted for connection with a brake pipe and a reservoir; an abutment in said body arranged to be actuated by the pressure d differential between brake pipe and reservoir;

and means operatively associated with said abutment, and arranged to afford normal communication between the brake pipe and reservoir when brake pipe pressure rises normally, a more re- 0 stricted communication when brake pipe pressure rises abnormally high, and a more free than normal communication when brake pipe pressure falls from an abnormally high to normal pressure. 5

CHARLES A. CAMPBELL. 

